Revert "Generate semconv/v1.40.0" (#7978)

Reverts #7929

Author: dmathieu

CHANGELOG.md

@@ -14,9 +14,6 @@ The next release will require at least [Go 1.25].
 ### Added
 
 - Support testing of [Go 1.26]. (#7902)
-- Add `go.opentelemetry.io/otel/semconv/v1.40.0` package.
-  The package contains semantic conventions from the `v1.40.0` version of the OpenTelemetry Semantic Conventions.
-  See the [migration documentation](./semconv/v1.40.0/MIGRATION.md) for information on how to upgrade from `go.opentelemetry.io/otel/semconv/v1.39.0.`(#7929)
 
 ### Fixed